This invention relates to a start-up power supply for a television receiver.
It is preferable to manufacture "cold" chassis designs for television receivers in which the power line is isolated from as much of the chassis as possible to minimize the possibility of electrical shock to the operator. One cold chassis design does not utilize a power line frequency (i.e., 60 Hz) transformer but develops directly from the power line a direct current potential necessary to provide power to the horizontal deflection system. The high voltage transformer which is driven by the horizontal deflection system operates at approximately 15,750 Hz and provides various amplitudes of 15,750 Hz alternating current voltages on various isolated windings for developing direct current potential (B+) sources for operating various television receiver circuits. This technique reduces greatly the receiver transformer weight and still provides cold chassis operation.
The horizontal oscillator required to drive the horizontal deflection system is generally isolated from the power line and, therefore, must be provided an isolated source of B+. Since the isolated source of B+ obtained from the high voltage transformer is not developed until the horizontal oscillator is in operation, an isolated source of B+ must be provided during a start-up interval.